The present invention relates to apparatus and systems for conserving heat energy in a closed environment. More particularly, the present invention relates to apparatus and systems for retrieving excess heat as from a fireplace, for efficiently storing heat in a liquid medium, for distributing heat from a heat source or heat storage and for utilizing a fireplace for not only direct air and liquid medium heating but also for delayed air heating when there is no combustion in the fireplace. The present invention is particularly useful for heating of homes, buildings or other closed environments.
It has long been known that a relatively large percentage of combustion heat from fireplaces, furnaces and the like is lost with the flue gases. Thus jacketed fireboxes which pass cool air around the firebox walls and exhaust it to the room have been in use for many years. An example is the 1894 issued U.S. Pat. No. 513,842 by Treiber which included water coils passing through the air jacket to provide bath water heating. A more recent arrangement for fireplace heat recovery improvement is shown in U.S. Pat. No. 4,050,441 by Horwinski wherein air from the jacketed firebox is passed through a series of finned tubes traversing the flue before exhausting into the room. Others have suggested recovery of fireplace heat by water filled jackets so that the heated water can be transferred to storage and subsequently used for other purposes as in U.S. Pat. No. 2,046,051 by Baruch et al. Tortuous water pipe systems through heated firebox flue gases to warm water for transfer to remote locations is shown in U.S. Pat. No. 2,622,587 by Dupler. Another system using a water jacketed firebox to warm water for transfer to remote heat radiators is shown in U.S. Pat. No. 1,391,394 by Loyer. An arrangement for heating for heating water in pipes passing through side air chambers of an air jacketed type of firebox for transfer of the heated water to storage so that the warmed water can later be passed back through those pipes to warm the air in the side chambers is shown in U.S. Pat. No. 4,050,626 by Awalt.
Despite the various efforts to improve fireplace combustion heat recovery efficiency over the years, none has gained acceptance to any significant degree. However, the sharply enhanced concern for energy conservation of recent years has brought on renewed interest in the rudimentary air jacketed fireplace wherein heated air is released into the same room as the fireplace, these being sometimes referred to as heatolator systems. Such systems suffer the disadvantages of only slightly improving heat recovery efficiency while frequently exhausting more heat than is required for the room during the time there is a fire in the firebox. Although storage of at least some of the excess combustion heat through transfer of water heated in the firebox has been suggested as in the devices of Treiber, Baruch et al, Awalt and others, none of the prior art teaches acceptably efficient fireplace configurations which can be used to return the stored heat to the environment around the fireplace in an effective manner nor do they suggest such a fireplace that can be practically integrated into a heating system for a building or the like. Awalt mentions return of stored heat to the firebox chambers for radiation in the absence of combustion but the device shown by Awalt is inherently unsatisfactory for efficient heat storing or returning and further neither suggests nor is well suited for integration into a overall heat distribution system.
With the recent advent of increased interest in heat conservation, there has been a concurrent demand for more efficient heated water storage apparatus which will ensure that the warmest water possible is available for subsequent heat delivery purposes. One effort to improve tank storage efficiency is shown in FIG. 6 of U.S. Pat. No. 4,127,103 by Klank and Jensen wherein the storage tank is segregated into sections by baffles with the warmed water injected at the upper baffle and the cool return water injected at the lower baffle.